As for hardware quality, I assume PS2 and Xbox are both more vulnerable than GameCube from what I hear, but Xbox disc scratching problem in Japan is one of factual accounts.
Frankly I think existing consoles are built more reliably (and more sturdy) then tons of other electronic machines we used over the years.
Eg. - Amigas were one fragile piece of machinery (although admitedly my abuse put my A500 through extremes) - I would never dream dropping one from 50cm-1m and expect it nothing to break.
PS2 survived that though (no I didn't do it on purpose, I swear). Jap launch unit still works too, inspite of all the office abuse. I figure PSTwo will be even better for doing this since it's lighter
Actually my complaint is really with the DTL10000 kits, their drives freaking fail all the time due to dust accumulation (I barely ever use the drive, actually for past 2 years, I never touched it) - first the discs stop being recognized, and the final stage is when the tray door simply refuses to open. But at least it's consistent, so far it happened on every devkit that has accumulated enough dust.
Oh while I'm babbling, I mistakenly put PSP controller/prototype through a er... "stress test", and it took it about as well as a DualShock2.
Now, a DS2 will take several months of being mistakenly dropped from a table like that until it starts showing damage (I've tested this with many units, so it's pretty reliable
), first only internal (you'll hear rattling noise when you shake it) and with continued abuse, the casing may eventually crack (only managed it with one unit so far).
But I should note PSP casing feels a lot sturdier then DS2... Definately also way more sturdy then any other mobile device I've used (PPCs I always worry they'll just break from holding them and if you seriously use it, expect screen to be scratched to hell just from the stylus use within a year... at least with any IPAQ model. GBA plastic also feels fragile in comparison, and don't even get me started on the mobile phones).
Only question is how resiliant the mechanical parts of the UMD are...